Brodie Croyle will be the starting quarterback when the Chiefs finish their exhibition schedule with Thursday night&rsquo;s game against the Rams in St. Louis. The bigger issue is whether Croyle will start the regular-season opener Sept. 13 in Baltimore if the injured Matt Cassel isn&rsquo;t available. Whether the starter is Croyle or Tyler Thigpen could depend in large part on how each player fares in St. Louis.